Workbench: Add pkgx.

Not sure about this one so let's try it out.

workbench/Dockerfile

@@ -260,6 +260,7 @@ RUN install -m 0755 <(curl https://raw.githubusercontent.com/rabbitmq/rabbitmq-s
     install -m 0755 <(curl "https://github.com/docker/compose/releases/download/v2.22.0/docker-compose-linux-$(uname -m)") /usr/local/bin/docker-compose && \
     install -m 0755 <(curl "https://github.com/genuinetools/reg/releases/download/v0.16.1/reg-$(go env GOOS)-$(go env GOARCH)") /usr/local/bin/reg && \
     install -m 0755 <(curl "https://github.com/rancher/rke/releases/download/v1.4.10/rke_$(go env GOOS)-$(go env GOARCH)") /usr/local/bin/rke && \
+    install -m 0755 <(curl "https://pkgx.sh/Linux/$(uname -m)") /usr/local/bin/pkgx && \
     mkdir /usr/local/share/bfg && \
     install <(curl 'https://repo1.maven.org/maven2/com/madgag/bfg/1.14.0/bfg-1.14.0.jar') /usr/local/share/bfg/bfg.jar && \
     curl https://github.com/SelfAdjointOperator/better-adb-sync/archive/refs/heads/master.tar.gz | tar -zxC /opt/ && \